Routes to Develop Fine-Grained Magnesium Alloys and Composites for High-Strain Rate Superplasticity

1999 ◽  
Vol 601 ◽  
Author(s):  
Toshiji Mukai ◽  
Hiroyuki Watanabe ◽  
T. G. Nieh ◽  
Kenji Higashi
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Magnesium Alloys ◽  
High Strain ◽  
Thermomechanical Processing ◽  
Superplastic Forming ◽  
Fine Grained ◽  
Superplastic Properties ◽  
Rapidly Solidified

AbstractSuperplastic properties of magnesium alloys and their composites were reviewed with a special emphasis on the achievement of high strain rate superplastic forming. The role of grain size on superplastic deformation mechanisms was particularly addressed. Commercial Mg-Al-Zn alloys and a ZK60-based composite are used as model materials to illustrate the underlining principles leading to the observation of high strain rate superplasticity. In this paper, experimental results from several processing routes, including thermomechanical processing, severe plastic deformation, and extrusion of machined chips and rapidly solidified powders, are presented. High strain rate superplasticity (HSRS) is demonstrated in ZK60-based composites.

Microstructure Change During High Strain Rate Superplastic Deformation in a PM 7475 AL-0. 7ZR Alloy

1990 ◽  
Vol 196 ◽  
Author(s):  
K. Matsuki ◽  
M. Tokizawa ◽  
Y. Murakami
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Subgrain Size ◽  
Early Stage ◽  
Strain Rate Range ◽  
Al Alloy ◽  
Subgrain Structure ◽  
Superplastic Properties ◽  
Rapidly Solidified

ABSTRACTImprovements of superplasticity in the high strain rate range have been achieved in a 7475 Al alloy with 0. 7 wt% Zr produced from rapidly solidified powder (PM7475-0.7Zr alloy), and the superplastic properties and microstructural changes with strain have been investigated.The PM 7475-0.7 Zr alloy has a cold rolling structure, but on heating to the superplastic temperature of 520°C, the alloy developed a very fine subgrain structure of average subgrain size of less than 1 μm. The fine structure was stabilized with metastable cubic Al3Zr precipitate dispersions, and there exist a large number of less than 5° misorientation subboundaries together with a small number of highly misoriented ones.After 117% strain at the high strain rate of 2. 5×10−1 S−1 the subboundaries with the misorientation of 5° – 15° Were observed to increase. During the initial stage of the deformation, m value and the contribution of boundary sliding to the deformation also increased with strain, and thus the alloy behaved superplastically during the following deformation.The improvements of superplasticity with strain in the early stage of the high strain rate deformation of the alloy were interpreted to be closely related with the increase in misorientation of subboundaries stabilized with finely dispersed metastable Al3Zr precipitates.

scholarly journals High-strain-rate nanoindentation behavior of fine-grained magnesium alloys

2012 ◽  
Vol 27 (9) ◽  
pp. 1295-1302 ◽  
Author(s):  
Hidetoshi Somekawa ◽  
Christopher A. Schuh
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Magnesium Alloys ◽  
High Strain ◽  
Fine Grained ◽  
Image Position

Abstract

scholarly journals Fracture behavior of twin induced ultra-fine grained ZK61 magnesium alloy under high strain rate compression

2019 ◽  
Vol 8 (4) ◽  
pp. 3475-3486 ◽  
Author(s):  
Abdul Malik ◽  
Wang Yangwei ◽  
Cheng Huanwu ◽  
Muhammad Abubaker Khan ◽  
Faisal Nazeer ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Fracture Behavior ◽  
High Strain ◽  
Fine Grained ◽  
Strain Rate Compression

High Strain Rate Superplasticity in a Zr and Sc Modified 7075 Aluminum Alloy Produced by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 164-169 ◽  
Author(s):  
Krystof Turba ◽  
Premysl Malek ◽  
Edgar F. Rauch ◽  
Miroslav Cieslar
Keyword(s):  
Aluminum Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Rate Sensitivity ◽  
7075 Aluminum Alloy ◽  
Fine Grained ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Elongation To Failure

Equal-channel angular pressing (ECAP) at 443 K was used to introduce an ultra-fine grained (UFG) microstructure to a Zr and Sc modified 7075 aluminum alloy. Using the methods of TEM and EBSD, an average grain size of 0.6 1m was recorded after the pressing. The UFG microstructure remained very stable up to the temperature of 723 K, where the material exhibited high strain rate superplasticity (HSRSP) with elongations to failure of 610 % and 410 % at initial strain rates of 6.4 x 10-2 s-1 and 1 x 10-1 s-1, respectively. A strain rate sensitivity parameter m in the vicinity of 0.45 was observed at temperatures as high as 773 K. At this temperature, the material still reached an elongation to failure of 430 % at 2 x 10-2 s-1. These results confirm the stabilizing effect of the Zr and Sc additions on the UFG microstructure in a 7XXX series aluminum alloy produced by severe plastic deformation.

Tensile Ductility of Ultra-Fine Grained Copper at High Strain Rate

2010 ◽  
Vol 160-162 ◽  
pp. 260-266 ◽  
Author(s):  
Tao Suo ◽  
Kui Xie ◽  
Yu Long Li ◽  
Feng Zhao ◽  
Qiong Deng
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Testing Machine ◽  
Coarse Grained ◽  
Dislocation Dynamic ◽  
Pressing Method ◽  
Fine Grained ◽  
Angular Pressing ◽  
Split Hopkinson

In this paper, ultra-fine grained copper fabricated by equal channel angular pressing method and annealed coarse grained copper were tensioned under both quasi-static and dynamic loading conditions using an electronic universal testing machine and the split Hopkinson tension bar respectively. The rapture surface of specimen was also observed via a Scanning Electron Microscope (SEM). The experimental results show that the ductility of polycrystalline copper decreases remarkably due to the grain refinement. However, with the increase of applied strain rate, ductility of the UFG-Cu is enhanced. The fracture morphologies also give the evidence of enhanced ductility of UFG-Cu at high strain rate. It is believed the enhanced ductility of UFG materials at high strain rate can be attributed to the restrained dislocation dynamic recovery.

High strain rate superplasticity in the fine-grained duplex stainless steel Fe-22Cr-5Ni-3Mo-0.3N

1996 ◽  
Vol 67 (10) ◽  
pp. 444-449 ◽  
Author(s):  
David Hernandez ◽  
Georg Frommeyer ◽  
Harald Hofmann
Keyword(s):  
Stainless Steel ◽  
High Strain Rate ◽  
Strain Rate ◽  
Duplex Stainless Steel ◽  
High Strain ◽  
Fine Grained
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